lesson 21, keyboard input and shell

21-shell/libc/mem.c

@@ -0,0 +1,13 @@
+#include "mem.h"
+
+void memory_copy(char *source, char *dest, int nbytes) {
+    int i;
+    for (i = 0; i < nbytes; i++) {
+        *(dest + i) = *(source + i);
+    }
+}
+
+void memory_set(u8 *dest, u8 val, u32 len) {
+    u8 *temp = (u8 *)dest;
+    for ( ; len != 0; len--) *temp++ = val;
+}